The family said doctors at Massachusetts General Hospital told them Campbell had survived -- but that they had to work hard to save her leg.

But when her parents were allowed to see her, they made a heart-wrenching discovery.

The wounded woman wasn't their daughter at all, but her close friend, Karen Rand, who had gone to see the race with her.

Rand had been carrying something with Campbell's name on it. Doctors saw it and assumed it belonged to the patient they were working on.

Rand survived, but Campbell, 29, did not.

Photos:Nation mourns Boston bombing victims

Photos:Nation mourns Boston bombing victims

Three people were killed when two homemade explosives went off at the Boston Marathon on April 15, 2013, and a campus police officer at the Massachusetts Institute of Technology was fatally shot in the manhunt that followed. From left, the victims were Krystle Campbell, Sean Collier, Lingzi Lu and Martin Richard. Click through the gallery to see how the victims were honored and remembered in the weeks after the terror attack.

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Photos:Nation mourns Boston bombing victims

People pause at the memorial site in Boston's Copley Square on April 30, 2013.

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Photos:Nation mourns Boston bombing victims

Running shoes were among the mementos left as a tribute to the bombing victims.

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Photos:Nation mourns Boston bombing victims

Boston showed its resilience and heart with signs of support for the bombing victims, including this cover from an issue of Boston magazine.

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Law enforcement officials enter St. Patrick's Church prior to Collier's funeral in Stoneham, Massachusetts, on April 23, 2013.

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President Barack Obama observes a moment of silence in the White House Oval Office on April 22, 2013.

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Staff members of the Beth Israel Deaconess Medical Center gather inside a trauma room to observe a moment of silence on April 22, 2013.

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A Buddhist sits at a memorial near the marathon finish line during a moment of silence on April 22, 2013.

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One week after the bombings, people gather to observe a moment of silence in Copley Square.

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Officials line Boylston Street as they observe a moment of silence near the marathon finish line on April 22, 2013.

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People take part in the moment of silence near the marathon finish line.

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State employees pause for a moment of silence on the steps of the Massachusetts State House.

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Pallbearers carry Campbell's casket after a funeral service in Medford, Massachusetts, on April 22, 2013.

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Mourners walk out of St. Joseph Catholic Church after Campbell's funeral service.

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Nurse practitioner Maureen Quaranto, who treated victims of the bombings, wears her Boston Marathon jacket during Mass on April 21, 2013.

Flowers, running shoes and other items are left in memory of bombing victim Lingzi Lu.

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Dennis Seidenberg of the Boston Bruins observes a moment of silence before the start of an NHL hockey game in Boston on April 17, 2013. It was the first sporting event held in the city after the bombings.

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Danielle Cerroni writes a chalk message on the street near the marathon's finish line on April 17, 2013.

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A woman looks at memorials left at the scene of the attack.

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A crowd gathers at Boston's Garvey Park during a vigil for bombing victim Martin Richard on April 16, 2013.

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A woman uses her hand to keep wind from her candle during an interfaith service in Boston on April 16, 2013.

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Mourners gather on the edge of the pond for a candlelight vigil in Boston on April 16, 2013.

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Students from the Clifden Academy hold an American flag and candles during a vigil in Dorcester, Massachusetts, on April 16, 2013.

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People walk along the barricade at Boylston Street on April 16, 2013.

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Mourners in Boston hug one another during a vigil for victims on April 16, 2013.

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Five-time Boston Marathon runner Jose Sotolongo, center, reacts during a moment of silence in Miami on April 16, 2013.

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The New York Islanders and Florida Panthers stand for a moment of silence before an NHL hocky game in Uniondale, New York, on April 16, 2013.

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Members of the Boston Red Sox observe a moment of silence before their Major League Baseball game in Cleveland on April 16, 2013.

Bombing victim's mom: Everyone loved her

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She is one of three people who perished when the two bombs blew shrapnel through crowds of thousands at the iconic road race.

Rolling up her sleeves

Campbell was driven by a strong work ethic, and it got noticed by family and coworkers alike.

Former employers commended her diligence when lamenting her death.

"She was one of the hardest workers that we had," said Nick Miminos, manager at Jimmy's Steer House, Campbell's most recent employer. "She would get in the trenches and work right next to you. She wasn't afraid to get her hands dirty."

"Full of energy and hard at work," is how former employer Summer Shack, a seafood restaurant, described her in a statement on its Facebook page.

She rolled up her sleeves with a smile, her grandmother Lillian Campbell told CNN's Jake Tapper. "She was very happy, outgoing, a hard worker."

Campbell lived with her grandmother for a year and a half and was "great with me," she said. She was always eager to help.

Her grieving mother, Patty Campbell, couldn't stop sobbing long enough to read a family statement to the press. To her, Campbell was nothing short of the best.

"You couldn't ask for a better daughter," she managed to get across her lips.

"She had a heart of gold. She was always smiling," Patty Campbell said, as her son, Billy, clutched her in his right arm.

Bright eyes, vibrant smile

Looking at Campbell's memorial page on Facebook, it's easy to believe her mother. The page is covered with photos of the young woman's vibrant smiles and bright eyes.

On the deceased restaurant manager's private page, the family points visitors to the memorial site, which had garnered over 51,000 likes by early Wednesday.

Admirers have left behind thousands of condolences and prayers.

"This just makes me so sad," Robert Zeff wrote on the Facebook page. "I'm so sorry for Krystle and everyone who knew her and loved her."